Derivatives

mesencephalic

Two non-sensory control regions were examined, the optic tectum and the mesencephalic tegmentum.

The root fibers arising from the trochlear nuclei form a decussation dorsal to the mesencephalic aqueduct, and they are the only cranial nerves that cross completely and that leave the dorsal aspect of the brain stem.

The principal mesencephalic projection to the striatum originates from the substantia nigra pars compacta.